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 *
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 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

import java.io.*;
import javax.mail.*;
import javax.mail.internet.*;
import javax.activation.*;

/**
 * This class models a UUEncoded Message sent from MS Outlook etc.
 * <p>
 *
 * The message structure looks like this := [text body] [uuencoded attachment]
 *
 * <p>
 * i.e., an optional text/plain main-body, followed by zero or more UUENCODE-ed
 * attachments.
 *
 * @author John Mani
 * @author Bill Shannon
 * @see javax.mail.internet.MimeMessage
 */
public class MSMessage extends MimeMessage {

    private String type;

    /**
     * Constructor that converts a MimeMessage object into a MSMessage.
     *
     * @exception MessagingException if the given MimeMessage is not a non-MIME
     * MS message, or if an IOException occurs when accessing the given
     * MimeMessage object
     */
    public MSMessage(Session session, MimeMessage msg)
            throws MessagingException {
        super(session);

        if (!isMSMessage(msg)) // sanity check
        {
            throw new MessagingException("Not an MS message");
        }

        class FastByteArrayOutputStream extends ByteArrayOutputStream {

            ByteArrayInputStream toByteArrayInputStream() {
                return new ByteArrayInputStream(buf, 0, count);
            }
        }

        // extract the bytes of the given message
        // ByteArrayOutputStream bos = new ByteArrayOutputStream();
        FastByteArrayOutputStream bos = new FastByteArrayOutputStream();
        try {
            msg.writeTo(bos);
        } catch (IOException ioex) {
            throw new MessagingException("IOException", ioex);
        } catch (Exception ex) {
            throw new MessagingException("Exception", ex);
        }
        //parse(new ByteArrayInputStream(bos.toByteArray()));
        parse(bos.toByteArrayInputStream());
    }

    /**
     * Constructor to create a MSMessage from the given InputStream.
     */
    public MSMessage(Session session, InputStream is)
            throws MessagingException {
        super(session); // setup headerstore etc
        parse(is);
    }

    // parse input stream
    protected void parse(InputStream is) throws MessagingException {
        // Create a buffered input stream for efficiency
        if (!(is instanceof ByteArrayInputStream)
                && !(is instanceof BufferedInputStream)) {
            is = new BufferedInputStream(is);
        }

        // Load headerstore
        headers.load(is);

        /*
         * Load the content into a byte[].
         * This byte[] is shared among the bodyparts.
         */
        try {
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            int b;
            // XXX - room for performance improvement
            while ((b = is.read()) != -1) {
                bos.write(b);
            }
            content = bos.toByteArray();
        } catch (IOException ioex) {
            throw new MessagingException("IOException", ioex);
        }

        /*
         * Check whether this is multipart.
         */
        boolean isMulti = false;
        // check for presence of X-MS-Attachment header
        String[] att = getHeader("X-MS-Attachment");
        if (att != null && att.length > 0) {
            isMulti = true;
        } else {
            /*
             * Fall back to scanning the content.
             * We scan the content until we find a sequence that looks
             * like the start of a uuencoded block, i.e., "<newline>begin".
             * If found, we claim that this is a multipart message.
             */
            for (int i = 0; i < content.length; i++) {
                int b = content[i] & 0xff; // mask higher byte
                if (b == '\r' || b == '\n') {
                    // start of a new line
                    if ((i + 5) < content.length) {
                        // can there be a "begin" now?
                        String s = toString(content, i + 1, i + 6);
                        if (s.equalsIgnoreCase("begin")) {
                            isMulti = true;
                            break;
                        }
                    }
                }
            }
        }

        if (isMulti) {
            type = "multipart/mixed";
            dh = new DataHandler(new MSMultipartDataSource(this, content));
        } else {
            type = "text/plain"; // charset = ?
            dh = new DataHandler(new MimePartDataSource(this));
        }

        modified = false;
    }

    /**
     * Return content-type
     */
    public String getContentType() throws MessagingException {
        return type;
    }

    /**
     * Return content-disposition
     */
    public String getDisposition() throws MessagingException {
        return "inline";
    }

    /**
     * Return content-transfer-encoding
     */
    public String getEncoding() throws MessagingException {
        return "7bit";
    }

    /**
     * Check whether the given MimeMessage object represents a non-MIME message
     * sent by Outlook. Such a message will have no MIME-Version header, may
     * have an X-Mailer header that includes the word "Microsoft", and will have
     * at least one X-MS-Attachment header.
     */
    public static boolean isMSMessage(MimeMessage msg)
            throws MessagingException {
        // Check whether the MIME header is present
        if (msg.getHeader("MIME-Version") != null) // MIME-Version header present, should be a MIME message
        {
            return false;
        }

        /*
         * XXX - disabled X-Mailer check because many sample messages
         * I saw didn't have an X-Mailer header at all.
         */
        if (false) {
            // Check X-Mailer
            String mailer = msg.getHeader("X-mailer", null);
            if (mailer == null) // No X-mailer ? 
            {
                return false; // Oh well !
            }
            if (mailer.indexOf("Microsoft") == -1) // Not MS stuff ?
            {
                return false;
            }
        }

        // Check X-MS-Attachment header
        // XXX - not all such messages have this header
        String[] att = msg.getHeader("X-MS-Attachment");
        if (att == null || att.length == 0) {
            return false;
        }

        return true;
    }

    // convert given byte array of ASCII characters to string
    static String toString(byte[] b, int start, int end) {
        int size = end - start;
        char[] theChars = new char[size];

        for (int i = 0, j = start; i < size;) {
            theChars[i++] = (char) b[j++];
        }
        return new String(theChars);
    }
}
